1. HNIDER S. M., WEBSTER G. M.: Am. J. Obst. & Gynec . 92 :891 , 1965 .
2. BRYAN W. M. Jr.: Am. J. Obst. & Gynec. 70: 1204, 1955.
3. RANDALL C. L., BAETZ R. W.: J. of the Obst. & Gynec. 3: 100, 1954.
4. STONE M., FOLSOME C. E.: Nonobstetric surgical complications of pregnancy. The Surgical Clinics of North America, April, 487, 1955.
5. HOFFMAN E. S., SUSUKY M.: Am. J. Obst. & Gynec. 67:1338, 1953.